Electric air heater



SePt- 27, 1932 E W, BALLENTINE 1,879,889

ELECTRIC AIR HEATERl Filed June 29, 1931 2 Sheets-Sheet 2 Q f M @mh @g f7@ e 5gg;

Patented Sept. 247, 1i932 UNITED STATES PATE NT oFr-icE EABLE W. BALLENTINE, OI' CHICAGO, ILLINOIS, ASSIGNOR TO SOLAR INDUSTRIES, INC.,

' A CORPORATION OIF ILLINOIS ELECTRIC In HEATER Application med inne 29,

This invention relates to improvements in electric heaters and, more especially, an electric air heater. I

Y Y' Among the features of my inventlon 1s the '5 .provision of such a heater that '1s st rong and rugged in construction, and eiiiclent 1n service and operation.

Another feature of my inventlon 1s the provision of a heater especially adapted for lo use with an electric fan to heat the current of air issuingfrom said fan. When used 1n this way, the heater will also operateas an air straightener. The heater is so made that the central part is substantially non-eifect1ve .15 so far as heating is concerned, thus particularly adapting the device for use with a fan mounted on a motor shaft where the motor blanks off the central part of the air stream.

` Other features and advantages of my 1nvention will a pear more fully as I proceed with my speci cation.

In that form of device embodying the features of my invention shown in the accompanying drawings- Figure 1 is aview in front elevation; Fig. 2 is a view taken as indicated by the line 2 of Fig. 1; and Fig. 3 is a. fragmentary view of the' heating .element with portions broken away to show the interior construction.

As shown in the drawings, the heater includes a substantially cylindricalcentral support 10, here shown as a hollow cylindrical casing closed at each end. Aroundthe central'support 10 is arranged an inner ring of substantially radial radiating iins 11, 11. As here shown, these fins are formed by reflexing a lstrip or` ribbon of metal. When thus formed, the ends of alternate parts of fins are attached by the portions of metal. 11a, such portions with the tins 11 forming one continuous strip or ribbon of sheet metal which is reflexed as above described to form the ring of radiating ins 11. Surrounding the inner ring of radiating fins 11 is a circular heating element 12, the detailed construction .are somewhat separated and bent outwardly,

1931. Seria1 No. 547,708.

of which will be described hereinafter. Arranged around and outside of the heating element 12 is an outer ring of radiating fins 13, 13. As here shown, these fins are also formed out of a single strip or ribbon of metal reflexed in the same manner as above described to form the inner ringof radiating fins 11. Around the outer ring of radiating fins is a. circular band 14, the ends of which as indicated by 14, to receive the bolts l5 which are tightened to contract the ring 14 to press the fins tightly against the heating element 12. This pressure' contact causes very efiicient and rapid transmission of heat '60 from the heating element to the fins with consequent rapid dissipation, thus contributing to the etliciency of the heater. Numerals 16, 16 `may indicate the lead wires to the heating element 12.

The heating element 12 may be formed in any desired manner. For'example, as here shown, the same includes an elongated metal sheath formed of ay strip of metal with its longitudinal edges folded over towards each other. For example, 12x1 may indicate one wall of the sheath, and 12b, 12b, the edges of the sheath folded over to form the opposite Wall thereof. Inside of the sheath is an insulated resistor, here shown as a refiexed flattened resistance wire 12c laid between two sheets of mica 12d, 12d. The element is -bent into circular form, as shown in Fig. 1, when it is placed in the heater.

The fins, band 14, central support and sheath of the heating element are preferably made of the same kind of metal or of different metals having substantially the same co-eflicient of expansion so that there will be no undesirable variations in tensions or pressures of the various parts of the heater with different temperatures. I found, for example, that aluminum or aluminum alloys are suitable for the manufacture of these parts.

lVith theconstruction shown, the band 14 may be drawn very tight and the tensile strength of the same utilized to give a very high and uniform compression or radial pressure inwardly to press the fins tightly against the'heating element. y

While I have shown and described certain embodiments of my invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and arrangement may -be made without departing from the spirit and scope of the invention as disclosed in the appended claims, in which it is my intention to claim all novelty inherent in my invention as broadly as permissible, in view of the prior art.

What I. regardas new, and desire to secure by Letters Patent, is:

, 1. A-n Aelectric heater, including; a ring of radiatingffins, 4 a circular heating element around the ring of radiating fins; and a circular band .around the fins and heating eleinent, said band being contracted to press the fins alga-instjthe heating element.

2. n electric heater, including; an inner ring of radiating fins; a circular heating element around the inner ring of radiating fins; an outer ring of radiating fins around the heating element; and a circular band 4around the outer ring of fins, said band being contracted to press the fins against the heating element.

3. An electric heater, including; a circular central support; a circular heating element around said support; a ring of radiating fins around said support and in contact with the heating element; and a circular band around the heating element and the ns, said band being contracted to compress the iins against the heating element.

4. An electric heater, including; a circular 4, in which the fins are radial and formed of a refiexed continuous strip of metal.

13. An electric heater as claimed in claim 1, in which the radiatin fins and circular b and are made of material having substantlally the same temperature co-efiicient of expans1on.

14. An electric heater as claimed in claim 2, in which the radiating fins and circular band are made of material having substantially1 the same temperature co-eiicient of expansion.

15. An electric heater as claimed in claim 3, in which the radiating fins and circular band are made of material havin substantially -the same temperature co-eiicient of expansion.

In witness whereof, I have hereunto set my hand this 26th day of June, 1931.

EARLE W. BALLENTINE.

central support; an inner ring of radiating f K fins around said support; a circular heating element around the inner ring of fins; an outer ring of radiating fins around the heating element; and a circular band around the outer ring of fins, to press the fins against vthe heating element.

5. An electric heater as claimed inclaim 1l, in which the fins are radial.

6. An electric heater as claimed in claim 2, in which the fins are radial.

7 An electric heater as claimed in claim 3, in which the fins are radial.

8. An electric heater as claimed in claim 4, in which the fins are radial.

9. An electric heater as claimed in claim 1,

said band being contracted in which the fins are radial and formed of a l refiexed continuous strip of metal.

10. An electric heater as claimed in claim 2, in which the fins are radial and formed of a relexed continuous strip of metal.

11. An electric heater as claimed in claim 3, in which the fins are radial and formed of a reflexcd continuous strip of metal.

12. An electric heater as claimed in claim llt 

